Despite all the headlines, Black Friday misbehavior is relatively rare. Police report a scattering of brawls, assaults and larcenies each year. But it's the headlines of far worse crimes that people remember.

A few years ago, gunfire erupted in a crowded Palm Desert Toys R Us, killing two people.

This year, the LAPD said it will be prepared. Helicopters will buzz above some shopping centers, and below, a cavalry of LAPD officers will patrol on bikes and horses. From store rooftops, officers will scan the crowds below looking for unruly behavior.

Electronic signs near stores will tell customers about how to avoid becoming theft victims as they navigate the mass of humanity looking for bargains.

The deployments are part of a new strategy by the LAPD to deal with the retail roller derby that comes after Thanksgiving. In addition to stationing officers around shopping centers, the LAPD has been visiting stores across the city this week, talking to managers about the psychology of the frantic shopper.

Officials said the push was prompted by a series of incidents at Black Friday sales, notably one last year at a Porter Ranch Wal-Mart in which two dozen people were injured when a woman unleashed pepper spray during a frantic battle for discounted video games.

The LAPD would not say exactly how many officers it will deploy Friday, but the number is expected to be considerable. In the Valley divisions, for example, officials have put together detailed tactical plans for each major shopping center, using mobile command posts and both officers and cadets.

Even some big retailers — which for years fueled the shopping frenzy with aggressive marketing and deep discounts — are trying to rein in some of the excitement they create this year.

Fernando Reyes, manager of the Wal-Mart in Porter Ranch where the pepper-spray incident occurred, said his main goal is to avoid a repeat of the chaos. He has met with the LAPD and plans new crowd-control strategies, including setting up special check-out lines for some sales items.